Method of producing a board of fibrous glass

ABSTRACT

Producing an asphaltic surfaced thermal insulating roofing board of bonded, randomly positioned and spacedly related individual, discontinuous glass fibers with short bundles or strands of glass fibers distributed in intermixed and bonded relation with the individual glass fibers throughout a comparatively narrow surface stratum of the board by forming and discharging individual, discontinuous fibers downwardly with particles of binder intermingled therewith upon a conveyor receiving surface, depositing bundles or strands of glass fibers with or upon the upper surface layer of the individual glass fibers of the deposited pack, compacting the pack in board form and curing the binder particles to dimensionally stabilize the pack in such form, applying heated asphalt to the upper surface and side edges of the compacted pack to impregnate the upper stratum thereof, applying a parting agent over the applied asphalt, and cooling the upper surface of the pack with water to set the asphalt.

United States Patent [191 Stapleiord et a1.

[451 Nov. 26, 1974 METHOD OF PRODUCING A BOARD OF FIBROUS GLASS [75]Inventors: Stuart 11. Stapleford, Atlanta, Ga.;

Charles E. Nutter, l-lebron, Ohio [73] Assignee: Owens-Corning FiberglasCorporation, Toledo, Ohio [22] Filed: June 18, 1973 [2]] Appl. No.:371,013

Related U.S. Application Data [63] Continuationof Ser. No.'874,428, Nov.6, 1969,

@, time Primary ExaminerRobert L. Lindsay, Jr. Attorney, Agent, orFirmCarl G. Staelin; John W. Overman; William P. Carr [5 7] ABSTRACTProducing an asphaltic surfaced thermal insulating roofing board ofbonded, randomly positioned and spacedly related individual,discontinuous glass fibers with short bundles or strands of glass fibersdistributed in intermixed and bonded relation with the individual glassfibers throughout a comparatively narrow surface stratum of the board byforming and discharging individual, discontinuous fibers downwardly withparticles of binder intermingled therewith upon a conveyor receivingsurface, depositing bundles or strands of glass fibers with or upon theupper surface layer of the individual glass fibers of the depositedpack, compacting the pack in board form and curing the binder particlesto dimensionally stabilize the pack in such form, applying heatedasphalt to the upper surface and side edges of the compacted pack toimpregnate the upper stratum thereof, applying a parting agent over theapplied asphalt, and cooling the upper surface of the pack with water toset the asphalt.

1 Claim, 8 Drawing Figures METHOD OF PRODUCING A BOARD OF FIBROUS GLASSThis is a continuation of application Ser. No. 874,428, filed Nov. 6,1969, and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a board composedprincipally of bonded fibrous glass and to such a board primarilyintended for roof insulation.

The roofing boards of this invention are designed mainly for flat orlow-pitched roof decks that may be surfaced with a built-upbitumen-bonded roofing. The boards are' laid directly over the roof deckwhether wood, steel, concrete or precast slabs.

BRIEF SUMMARY OF THE INVENTION A principal object of this invention is amethod of producing a roofing board by which the board may beeconomically and completely fabricated in a continuous production lineutilizing a reduced number of components and fewer steps in themanufacturing process.

A concomitant purpose is to provide an insulating board that amplifiesthe overall strength of a built-up roof structure.

A further object of the invention is a method of producing a generallyair permeated, thermal insulating fibrous board that has a stratum ofextra density and strength with exceptional resistance to compressiveand puncturing forces.

Another object of the invention is the processing of a roofing boardwith sufficient rigidity and attachment characteristics to withstanduplifting under high winds from its installed position in a roofstructure.

A still further object of this invention is a method of combiningstrands of fibrous glass with individual glass fibers in a stratum of afibrous board.

These and other objects and advantages of the invention are attainedprincipally through a method of constructing a fibrous board withrandomly positioned, individual, non-continuous glass fibers extendingin spaced and in resinously bonded relation throughout the full area ofthe board including a definite planar stratum thereof, having bundles orstrands of glass fibers in the planar stratum resinously bonded to thenon-continuous fibers, and having the stratum saturated and furtherbonded by an asphaltic or other resinous impregnation.

BRIEF DESCRIPTION .OF THE DRAWINGS The successful practice of theinvention is further promoted by supplemental features set forth in thesubsequent description-and accompanying drawings in which:

FIG. I is a longitudinal, partly sectional, elevational view ofa fiberforming and collecting apparatus including a series of rotary type fiberforming units, a fiber collecting conveyor, and compressing conveyorflights passing through a binder curing'oven;

FIG. 2 is a longitudinal vertical sectional view of a modified form ofthe invention including the lower portion of the last rotary type fiberforming unit of the series shown in FIG. 1;

FIG. 3 is a diagrammatic side elevational view of apparatus comprising acontinuation of the production line starting with the apparatus of FIGS.I and 2 and ineluding a conveyor, an asphalt applicator and otherprocessing devices;

FIG. 4 is a cross section of the apparatus of FIG. 3 taken on the line44 thereon;

FIG. 5 is a side elevation of a longitudinal portion of the conveyor ofFIG. 3 with associated devices adapted for practicing a modified methodof the invention;

FIG. 6 is a perspective view of a broken corner portion of a roofingboard produced by the modified method of the invention involving theapparatus of FIG. 5; and

FIGS. 7 and 8 are similar views of two other fibrous boards produced bythe methods of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in more detail to thedrawings, suitable equipment and processing procedure for fabricatingthe boards are presented in FIGS. 1, 2, 3, 4, and 5. At the start of-theproduction line of FIG. 1 there is shown a portion of a glass furnace 10with a forehearth 11 extending therefrom. A series of ported bushings 12are mounted upon the lower side of the forehearth 11. Streams 14 ofmolten glass issue downwardly from the bushings into a series of sevenrotary fiber forming units of which only three, 16 and 18, the firsttwo, and 20, the last of the series, are here illustrated.

The rotary forming units are all alike and of a conventional designincluding an upper housing 22 supported upon 'a carriage 24 movablymounted upon tracks 26. This arrangement permits each unit to betemporarily transferred from the hot area of the forehearth forinspection and maintenance requirements.

As may be seen in the sectioned portion of rotary unit 20, the stream 14of molten glass is directed downwardly through a hollow tube or quill 28extending from the upper end of housing 22 down to a centrifuge 30 towhich it is joined. The quill and centrifuge are rotatably driven by amotor within housing 22. The molen glass is fiberized by beingcentrifugally forced through orifices in the peripheral surface ofcentrifuge 30. From chamber 34 hot combustion gases are discharged downupon the upper surface of the centrifuge 30 to maintain it at moltenglass temperature. The primary fibers issuing laterally from theorificed peripheral surface of the centrifuge 30 are blown downwardlywithin the cylindrical shield 34 and are further attenuated therein by ablast of combustion gases from the annular burner 36. The resultingwhirling veil of fibers 38, with the combined stream of hot gases fromchamber 32 and burner 36, descends through guiding spout 40. The fibersmay be between twenty-five and sixty hundred thousandths of an inch indiameter but preferably have a diameter of approximately thirty-ninehundred thousandths.

A series of nozzles 42 around the lower edge of spout 40 projectresinous binder particles 44 into the veil of fibers 38 prior to theentry of the fibers into the forming hood 46. In this instance avertical partition 48 within the hood secludes the fibers from the lastrotary unit 20 the fibers produced by the preceding rotary units intheir descent to the foraminous conveyor 50, traveling over suctionchamber 52. Similary a partition 48a sequesters the fibers deliveredfrom the first unit 16.

Phenol formaldehyde is the preferred binding agent, but it has been wellestablished that various other resinous materials such as epoxies, ureaand malamine formaldehydes also give excellent results. The amount ofthe binder utilized is advisbly in the region of nine per cent by weightof the full fibrous pack but may be varied within a range of 5 to percent with the cost factor tending to discourage higher quantities, anddiminishing strength accompanying the use of lower amounts.

Chopped strands 57 are mixed with the fibers produced by rotary unit bycombination chopper and blower 56. This draws strands 54 from an alignedseries of strand packages such as the single spool or bobbin 55illustrated and projects the chopped strands into the upper end of.theportion of thehood 46 which is confined by partition 48.

The chopped strands 57 are desirably cut to lengths between 2 and 4inches and in the example of processing herein selected for purposes ofexplanation amount in weight to at least 10 per cent of the weight ofthe non-continuous fibers from rotary forming unit 20 with which theyare combined. With a conveyor speed of 60 feet per minute and adeposited fibrous pack 4 feet wide intended for forming a roofing boardone inch in thickness, the chopped strands would be introduced at therate of roughly 2 and /2 pounds per minute.

The basic strands 54 may be ofa size providing about 15.000yards perpound and be composed of 200 continuous filaments of an approximatediameter of thirty seven, hundred thousandths of an inch. Alternately,the individual strands may contain some 400 continuous filaments with adiameter around twenty five, hundred thousandths of an inch.

Feeding of the chopped strandsmay be considerably advanced by bundlingthem into loose rovings upon the packages 55 and passing the rovingsthrough the chopper 56. 6O strand ends may, for example, be so gatheredtogether in each roving and six or more of such rovings be fed in spacedrelation through the chopper 56, the latter being of appropriate length,such as four feet in this instance, to discharge the chopped strandsacross the width of the hood 46. Through the whirling and turbulentdownward movement of the veil of the fibers 38 and binder particles 44in the accompanying combustion gases, the chopped strands 57 arethoroughly intermixed with thefibers.

Other forms of strands of filaments in side by side, parallel relationincluding fibrous glass yarns and cords in short or continuous lengthsmay be utilized in differing quantities for effective practice of theinvention.

The pack 58 accumulated within hood 46 includes the fibers produced bythe full series of seven rotary fiber forming units. As the fibers fromrotary unit 20 are the last to be deposited upon the pack 58 there isformed a distinct upper stratum 62 constituting adefinite proportion. inthis instance one seventh, of the total thickness of the pack 58,throughout which the chopped strands are exclusively distributed.

If it is desired to have a strengthening stratum on the bottom of thepack 58, in addition to the upper stratum 62, strands are fed to thechopper 56a to project chopped strands into intermingling relation withthe fibers downwardly discharged from the first fiberizing rotary unit16. The fibers from this unit and the chopped strands added thereto aresegregated during their descent and deposit upon the conveyor 50 by thepartition 48a.

In case a more concentrated and thinner upper stratum including choppedstrands 57 is preferred, the latter may be added with the modifiedstructure illustrated in FIG. 2. In this arrangement a separate downwardchannel adjacent theoutlet of the hood 46 is provided by supplementalwall 59. Chopped strands are directed into this channel by chopper andair gun 56b.

The pack 58 is carried by conveyor 50 under roller 64, which ispreferably heated to decrease the propensity of the fibers to becomeattached thereto, and the pack is preliminarily reduced thereby to acompressed state 66 for introduction between upper and lower compressionconveyor flights 70 and 72 within oven 68. The thickness of the pack ispermanently established by the setting of the binder within the oven. Acontinuous rigid panel 74 with a strand reinforced upper stratum 62, andin the thickness of 1 inch in this instance, is accordingly dischargedfrom the oven.

The density of the panel 74 in its final compressed state should not bebelow 7 and /2 pounds per cubic foot in order to maintain highcompressive strength in the fibrous boards, and preferably should notexceed 9 pounds for retention of the porosity required for superiorthermal insulation.

From the oven 68 of FIG. 1 the panel 74 with its upper stratum 62reinforced with chopped strands 57 moves along the conveyor line 76diagrammatically shown in FIG. 3. As a final step of processingprocedure followed along conveyor line 76, a vertically reciprocatingchopping knife 78 severs the panel 74 crosswise into individual boardunits 79. The panel 74 is usually four feet in width, standard fixeddimension of the roofing boards. According to the timing of operation ofthe knife 78 the other planar dimension of the boards may be within abroad range but most commonly is wither 2, 3 or 4 feet.

Residual heat from the binder curing temperature utilized in the oven isretained in the panel 74 as it passes beneath the asphalt coater 80 towhich asphalt in a controlled volume is delivered by pump 86. Thedesired fluidity of the asphalt passing through the coater is maintainedby an associated heater 88.

A thin continuous curtain 81 of asphalt flows downwardly from the coateracross the upper surface and slightly over the edges of the boards 79whereby the side edge surfaces are also coated as may be best seen inFIG. 4. 7

Due to the porosity of the panel 74 the asphalt-sinks into the upperstratum 62 thereof and slightly into the surfaces of the opposite sideedge portions. The penetration of the asphalt is predetermined by theamount thereof, its controlled fluidity and supplementally by thehardening of the asphalt from the chilling effect of the high watercontent of the parting agent 94 subsequently discharged upon the boardsby a crosswise series of nozzles 92.

Through this controlled entry, the asphalt impregnation is restricted tothe full or major portion ofthe thickness of upper stratum 62 amountingin this example to one seventh of the full thickness of the panel 74.The high porosity and attendant thermal insulating capacity of the mainportion of the panel is thus preserved.

The preferred asphalt for impregnation of the upper stratum is a steepasphalt having a softening point between and F. One having a softeningpoint below 170F is not recommended while asphalts with melting pointsas high as 250F would ordinarily give very satisfactory service. In theapplicator 80 the asphalt is maintained at the desired fluidity by beingheated to between 340 and 410F and normally between 350 and 375F.

From approximately 4 to 7 and /2 ounces of the asphalt is applied toeach square foot of surface of the panel 74. The maximum is sufficientto thoroughly saturate the upper stratum 62, with some asphalt in anycase retained upon the surface of the units. The rather rough surface ofthe basic fibrous glass panel derived from conveyor flight impressionand the fibrous stock cooperates with the surface asphalt for attachingengagement with roofing materials which may later by superimposed uponthe boards.

While a steep asphalt is preferably utilized other bituminous materialsmay serve adequately and the term asphalt when appearing herein shouldbe interpreted as possibly containing asphaltenes, tarry substances,petroleum residues, pitches, road oils, albino asphalt, cut-backs,solutions or dispersions and cracked, straight run or natural asphalts.

The final hardening of the asphalt and cooling of the panel is furtherpromoted by the spraying of water from nozzle means 96 and high velocityair jets from nozzles 98, the latter mainly utilized to drive andevaporate water from the surface of the panel.

The parting agent 94 forms a porous coating primarily for the purpose ofpreventing sticking of adjacent boards due to the asphalt impregnantwhen the boards are stacked in shipping packages. The parting agent is aheavily pigmented latex composition with a polyvinyl acetate or otherresinous base. It may be formulated according to Example 3 ofU.S. Pat.No. 3,239.475 modified by an increase of at least 50 and preferablyabout 100 per cent additional water and a reduction of lOper cent in thepigment content. The latex parting agent is applied in sufficientquantity to the surface of the panel 74 to leave after evaporation ofthe water vehicle about 3 and V2 grams of solids per square foot.

A comparatively low temperature of the parting agent dispersion and theevaporation action of the water content has a considerable coolingeffect on the asphalt impregnant and is a factor in determining thedepth of penetration.

Conversely, the residual heat of the panel 74 and of the asphaltpromotes the practically instantaneous setting of the parting agent.

.Apparatus for following an alternate form of the method of thisinvention is depicted in FIG. 5. As there shown a polyethylene film 101is directed down upon the panel 74 by rolls 103 and 105 as a partingagent in place of the material 94 applied by nozzles 92. A film one-halfa mil in thickness serves very satisfactory.

Roll 105 is chilled by water sprayed thereon by nozzles 106. This coolsthe film 101 and therethrough reduces the temperature of the asphaltimpregnation of the panel 74. Additional water and air cooling treatmentsuch as provided by nozzles 96 and '98 is not required. The film issoftened to a tacky condition by the residual heat of the asphalt and isthereby being attached to the panel. Guides 107 and rollers 108 turn theedges of the polyethylene film 101 downwardly and presses them inadhering relation against the side edges of the panel 74.

The film and roll 105 have a smoothing effect upon any concentration ofasphalt left upon the surface of the panel 74. Besides serving as a moreuniform parting agent than the material 94 when the resulting boards 79are stacked for shipping or storage, the film also facilitates handlingand installation of theboards.

Because of its lower melting point the polyethylene film is liquefiedand fuses with any hot asphalt that may be later mopped over the boards.

A corner ofa board produced by this invention is depicted in each ofFIGS. 6, 7, and 8. It is the same basic board in all views with an upperstratum 62, but respectively shown are the board with a protectivecovering of polyethylene and a lower stratum 109 as well as an upperstratum 62 (FIG. 6), prior to an impregnation of asphalt (FIG. 7), andafter such impregnation (FIG. 8).

Non-continuous glass fibers 38 extend throughout the boards inindividually spaced relation. Chopped strands S7 of fibrous glass aredispersed throughout the upper stratum 62 (and lower stratum 109) whichis comparably narrow in thickness with the chopped strands 57 uniformlyintermingled with the fibers 38.

Particles or small bodies 44 of binder are distributed throughout theboard and secure the fibers 38 together at their crossover points and tothe chopped strands 57.

There is a slightly higher concentration of the binder particles in thelower portion of the board. This provides this section of the board withadded rigidity and strength in relation to the midportion of the board,but still far below the upper stratum in these properties due to thepresence there of the reinforcement of the chopped strands.

The upper stratum 62 is solidified and further strengthened by theimpregnation thereof by steep asphalt 110 as shown in FlG. 8. Animpregnating coating of asphalt is also shown on one edge surface of theboard with only slight penetration. The limiting of asphalt to the upperstratum (and possibly also to the lower stratum should it be desired toinvert the boards and apply asphalt to a strand reinforced lowerstratum) and the side surface portion leaves the balance of the boardwith high porosity and accompanying excellent heat insulating capacity.

.This invention presents a method of producing a thermal insulatingboard primarily adapted for use in roofing. The method provides adensified stratum preferably adjoining the upper surface butpositionable alternately or additionally intermediately or in the lowerportion of the board. The stratum includes integrated fibrous glasselements such as chopped or continuous strands and may include in theupper and lower stratum a resinous impregnation, preferably of asphalt.

Particular steps of the method deserving emphasis include adding theglass strands to a whirling body of individual fibers, said body being adefinite temporarily segregated portion of primary fibers beingaccumulated in a fibrous pack, alternately adding strands to anassembled pack of individual fibers before the binder thereof is curedand before the pack is compressed to its final form, introducing animpregnating and sealing resinous material into stratums of fibrousboards, covering the surface of the compressed pack with a parting agentwhile the surface is still heated from the application of ahotimpregnant, utilizing a thermoplastic reslnous film for said partingagent, and reducing the temperature of the hot impregnant with theapplication of the parting agent.

As those skilled in the arts involved may easily perceive variousalterations and modifications may be made in the method of thisinvention without departing from the spirit thereof and the scope of thefollowing claims.

We claim:

1. A method of producing a thermal insulating roofing board of bonded,randomly positioned and spacedly related individual, discontinuous glassfibers with short bundles or strands of multiple glass filamentsdistributed in intermixed and bonded relation with the individual glassfibers throughout a narrow stratum of the board, said method comprisingdrawing individual fibers from molten glass and directing themdownwardly in spaced and randomly positioned relation toward atransversely traveling receiving surface, dividing the descending fibersinto separate groups, said groups positioned successively in thedirection of travel of the receiving surface, combining a dispersedsettable binder with the fibers of each group, combining andintermingling short bundles or strands of definite predetermined lengthsand containing hundreds of glass filaments with the individual fibersand dispersed binder of the group of fibers leading the succession ofgroups in the direction of travel of the receiving surface, whileleaving other groups free of such strands, whirling the fibers of theleading group around a vertical axis to mix together the fibers, thestrands, and binder thereof, maintaining the groups of fibers separatedthroughout their full downward travel, collecting the fibers, thedispersed binder of all groups and the fibrous glass strands of theleading group as a pack upon the receiving surface, compressing the packand setting the dispersed binder to dimensionally stabilize the pack inboard form by cohering the fibers throughout the pack and cohering thefibers and the strands in the surface stratum thereof constituting thefibers and strands of the leading group deposited last upon the pack inthe movement of the receiving surface.

1. A method of producing a thermal insulating roofing board of bonded,randomly positioned and spacedly related individual, discontinuous glassfibers with short bundles or strands of multiple glass filamentsdistributed in intermixed and bonded relation with the individual glassfibers throughout a narrow surface of the board, said method comprisingdrawing individual fibers from molten glass and directing themdownwardly in spaced and randomly positioned relation toward atransversely traveling receiving surface, dividing the descending fibersinto separate groups, said groups positioned successively in thedirection of travel of the receiving surface, combining a dispersedsettable binder with the fibers of each group, combining andintermingling short bundles or strands of definite predetermined lengthsand containing hundreds of glass filaments with the individual fibersand dispersed binder of the group of fibers leading the succession ofgroups in the direction of travel of the receiving surface, whileleaving other groups free of such strands, whirling the fibers of theleading group around a vertical axis to mix together the fibers, thestrands, and binder thereof, maintaining the groups of fibers separatedthroughout their full downward travel, collecting the fibers, thedispersed binder of all groups and the fibrous glass strands of theleading group as a pack upon the receiving surface, compressing the packand setting the dispersed binder to dimensionally stabilize the pack inboard form by cohering the fibers throughout the pack and cohering thefibers and the strands in the surface stratum thereof constituting thefibers and strands of the leading group deposited last upon the pack inthe movement of the receiving surface.